Mold for centrifugal casting



Patented Dec. 8, 1925.

NTED STATES LEON CAMMEN, on NEW Yoan, N. Y.

MOLD FOR CENTRIFUGAL CASTING'.

Application med Maren 13, 1925. seriai No. 15,27,

To aZZ- whom 'it may concern:

Be it known that I, LiaoN CAMMEN, a citizen of the United States, andresiding in the borough of Manhattan, in the city, county, and State ofNew York, have in vented certain useful Improvements in Molds forCentrifugal Casting, of which the following is a specification.

The present invention` refers to an improvement in molds for centrifugalcasting, in particular those provided with dividing hars, such asareused for the production of ingots, billets, sheet bars and the like.

The illustration shows a section of the mold in a plane normal to theaxis of rotation.

The inner surface of molds for the centri'fugal casting of tubes issimple to make. as it is merely a cylinder, and can be bored to finishsize andv shape in the usual lathe or boring mill'. Diiculties in makingmolds arose however lately, With the de'- velopment of thecomparatively` new art of casting centrifugally, in a horizontal mold,ingots, sheet bars and the like. Such molds require dividing bars orlugs, such as 1 and 2, to separate the individual ingots (cp. TheFoundry rlrade Journal, August 28, 1924, 178, and iron A ge, J une 26,1924, p. 1857 These dividing bars may be machined out of the same stockas the rest of' the mold, or may be made out of separate pieces ofmetal. Inthe former of these two cases /the trouble which this invention'conteurplates to Obviate, does not occur, but where the dividing barsare made of separate pieces, and merely attached to the mold by somemeans, such as bolting, screwing, or edge welding,-the following troublemay occur. p

As molten metal, such as steel, is poured into 'the mold and as it thenfreezes, its heat is mainly carried off by the metal of the moldy andthe metal of the lbars (some heat being also lost by radiation andconvection through .the air). The mold is however a very large body ofmetal as compared with the dividing, bars, and it is obviously veryimportant that as much heat as possible should be handled by the mold,

The

and as little as possible by the bars. only way to accomplish this is topermit an easy ow of heat from the bars to the mold. It has been foundhowever that aflow of heat between two bodies of metal occurs easilyonly when there is a molec- 1ila'r continuity between the bodies, i. e,When they are united by a body of metal, such as may be produced bywelding, soldering or brazing. On the other hand, where the Contactbetween the two bodies of metal is a purely. mechanical one, as inbolted or riveted joints,.the flow of heat between the two bodies ofmetal is very poor even when the surfaces seem to fit together extremelyWell.

Applying the above reasoning to the case of molds for centrifugalcasting,it should be borne in mind'that these molds may be of very largedimensions, such as 100 in."

inside diameter, and 16 ft. long, While the bars may be 8 to 10 in. wideat the bottom, and that the life of such molds in casting steel is atbest comparatively .short which makes'it imperative to be able' toproduce the molds'at a fairly low cost, which means that only a veryrough t can be attempted between the dividing bars and the barrel of themold 3. But if a mold were used with such a rough fit between thedividing metal like steel is cast. With wide bars welding cannot be usedeither for obvious reasons, and of course where vit can be usednecessary to resort to the employment of the present invention, theselection between the` two methods being a matter which any4 may skilledin the art can 'decide for himself.

vbars and the barrel of the mold, the bars .p

Neither soldering nor brazing can vbe used, however, where a hightemperature conveniently. and cheaply, it might not be In the presentinvention the dividing bar is nished without any attempt at producing agood fit between it and the barrel; on the contrary, 'it is ratheradvisable to makethe t pool, somewhat like that shown in the drawing.`The next step is to paint or varnish all the surfaces ofthe interior ofthe barrel and of the bars, except those corresponding to those between4 and. 5 on thev bars, and those between 6 and 7 on the' f barrel. Thebarrel is then closed at both ends, lilled with a proper electrolyte, ametallic anode 8 is introduced, and current is applied in such a manneras Vto deposit a metallic layer between the bar and the barrel of themold.- The metal need not necessarily be the same as that of the bars orbarrel of the mold. It may not always be possible to produce a perfectdeposit between the bar and the barrel in the sense that there mayremain places, as for example, between 4 and 9, where the deposit wouldbe poor, but this is immaterial as long asy enough deposited metal isavailable to carry all the heat from the bar into the barrel of the moldin a manner to equalize their temperatures. VThe tips of the bars, suchas 5, may be then spot-welded to the barrel if desired.

AsV centrifugal casting of objects other than tubes is,'commercially, anew art, its terminology is still Vague, and the parts which have beenhere referred to as di. viding bars, are also described as partiu tionlu s, shapes, projections, etc.

2. A mold for centrifugal casting equipped with projection lugs made of'pieces different from the barrel of the mold Whereinthe lugs are securedto the barrell by a continuous metallic joint, and the tips of the lugsare welded to the barrel. y

3. Almold for centrifugal casting consisting of a barrel, projectionlugs and metallic joints between said barrel and lugs consisting ofeletrodeposited metal.

4. A mold for centrifugal casting consisting of a barrel, projectionlugs and metallic joints between said barrel and lugs consisting ofelect'rodeposited metal, the tips of the lugs being welded tothe barrel.

Signed in New York, in the county and State of New York, February 16,'1925.

LEON CAMMEN.

